7 research outputs found
Highly anisotropic transient optical response of charge density wave order in ZrTe
Low dimensionality in CDW systems leads to anisotropic optical properties, in
both equilibrium and non-equilibrium conditions. Here we perform polarized
two-color pump probe measurements on a quasi-1D material ZrTe, in order to
study the anisotropic transient optical response in the CDW state. Profound
in-plane anisotropy is observed with respect to polarization of probe photons.
Below both the quasi-particle relaxation signal and amplitude
mode (AM) oscillation signal are much larger with
nearly parallel to axis () than for
parallel to axis (). This reveals that signal is
much more sensitive to the variation of the CDW gap. Interestingly, the
lifetime of the AM oscillations observed with is longer than . Moreover, at high pump
fluence where the electronic order melts and the AM oscillations vanish for
, the AM oscillatory response still
persists for . We discuss possible origins
that lead to such unusual discrepancy between the two polarizations.Comment: 6 pages, 4 figure
Dynamics of collective modes in an unconventional charge density wave system BaNi2As2
BaNi 2As 2 is a non-magnetic analogue of BaFe2 As2 , the parent compound of a prototype
pnictide high-temperature superconductor, displaying superconductivity already at ambient
pressure. Recent diffraction studies demonstrated the existence of two types of periodic
lattice distortions above and below the triclinic phase transition, suggesting the existence of
an unconventional charge-density-wave (CDW) order. The suppression of CDW order upon
doping results in a sixfold increase in the superconducting transition temperature and
enhanced nematic fluctuations, suggesting CDW is competing with superconductivity. Here,
we apply time-resolved optical spectroscopy to investigate collective dynamics in BaNi 2 As 2.
We demonstrate the existence of several CDW amplitude modes. Their smooth evolution
through the structural phase transition implies the commensurate CDW order in the triclinic
phase evolves from the high-temperature unidirectional incommensurate CDW, and may
indeed trigger the structural phase transition. Excitation density dependence reveals excep-
tional resilience of CDW against perturbation, implying an unconventional origin of the
underlying electronic instability
Health-Seeking Behaviors and Self-Care Practices of People with Filarial Lymphoedema in Nepal: A Qualitative Study
Background. Lymphatic filariasis is endemic in Nepal. This study aimed to investigate health-seeking behaviors and self-care practices of people with filarial Lymphoedema in Nepal. Methods. A cross-sectional study was conducted using qualitative methods in three endemic districts. Twenty-three patients with current Lymphoedema were recruited in the study. Results. Hydrocele was found to be a well-known condition and a major health problem in the studied communities. People with Lymphoedema primarily sought health care from traditional healers, whereas sometimes home-based care was their first treatment. Later Ayurvedic and allopathic hospital-based care were sought. Respondents reported various psychological problems such as difficulty in engaging in sexual intercourse, anxiety, worry and stress, depression, low self-esteem, feeling weak, fear of being abandoned, and fear of transmitting disease to the children. Standard foot care practices except washing were largely absent. Conclusions. Lymphoedema in the limbs and hydrocele were found to be major health problems. The traditional health care providers were the first contact of care for the majority of respondents. Only a few patients had been practicing standard foot care practices
Disseminated toxocariasis in an immunocompetent host
Toxocariasis is a zoonotic infection caused by Toxocara canis, or less commonly, Toxocara cati, which is one of the most common zoonotic infections worldwide. It commonly affects the pediatric and immunocompromised population; however, it has rarely been reported in the immunocompetent adults. Two of the well-recognized syndromes in children are visceral larva migrans and ocular larva migrans. Infection in adults usually ranges from asymptomatic to non-specific symptoms which makes the diagnosis challenging. A case of 36 year-old male was presented with disseminated toxocariasis with pulmonary and hepatic involvement and striking peripheral eosinophilia
Optically Triggered Néel Vector Manipulation of a Metallic Antiferromagnet Mn2Au under Strain
International audienceThe absence of stray fields, their insensitivity to external magnetic fields, and ultrafast dynamics make antiferromagnets promising candidates for active elements in spintronic devices. Here, we demonstrate manipulation of the Néel vector in the metallic collinear antiferromagnet Mn2Au by combining strain and femtosecond laser excitation. Applying tensile strain along either of the two in-plane easy axes and locally exciting the sample by a train of femtosecond pulses, we align the Néel vector along the direction controlled by the applied strain. The dependence on the laser fluence and strain suggests the alignment is a result of optically-triggered depinning of 90o domain walls and their sliding in the direction of the free energy gradient, governed by the magneto-elastic coupling. The resulting, switchable, state is stable at room temperature and insensitive to magnetic fields. Such an approach may provide ways to realize robust high-density memory device with switching timescales in the picosecond range
Optically Triggered Néel Vector Manipulation of a Metallic Antiferromagnet Mn<sub>2</sub>Au under Strain
The absence of stray fields, their insensitivity to external
magnetic
fields, and ultrafast dynamics make antiferromagnets promising candidates
for active elements in spintronic devices. Here, we demonstrate manipulation
of the Néel vector in the metallic collinear antiferromagnet
Mn2Au by combining strain and femtosecond laser excitation.
Applying tensile strain along either of the two in-plane easy axes
and locally exciting the sample by a train of femtosecond pulses,
we align the Néel vector along the direction controlled by
the applied strain. The dependence on the laser fluence and strain
suggests the alignment is a result of optically triggered depinning
of 90° domain walls and their motion in the direction of the
free energy gradient, governed by the magneto-elastic coupling. The
resulting, switchable state is stable at room temperature and insensitive
to magnetic fields. Such an approach may provide ways to realize robust
high-density memory device with switching time scales in the picosecond
range